RuO2-IrO2-TiO2 coatings on titanium electrodes prepared by thermal decomposition have been characterized by scanning electron microscopy, x-ray diffraction analysis (XRD), x-ray photoelectron spectroscopy (XPS), thermal desorption spectrometry (TDS), andy, cyclic voltammetry (CV). The XRD results indicated that the mixed oxide coatings formed a three-component solid solution. The TDS and the CV were applied for quantitative analysis of surface RuO2 content. The chemical composition examined by XPS, TDS, and CV showed that the surface RuO2 Content was lower than the nominal content. The XPS results, however, deviated considerably from those of TDS and CV The XPS method can detect the elements only at the outer surface of rough textures, whereas the other two methods can reflect the RUO2 content of both the outer and the inner surface, including pores and intergrain regions, of the coatings. This means that TDS and CV are useful in the investigation of the surface composition of Ru-base mixed oxide electrodes.